Variable-capacity compressor.



-B. V. NORDBERG.

, VARIABLE CAPACITY oomrnnsson.

, APPLIOATIOH TILED SEPT. 8, 1903. 900,41 8, Patented Oct. 6, 1908.

' APPLICATION FILED SBPTLB, 1903..

B. v. NORDBBRG.- VARIABLE CAPACITY comunsson; 1'

Patented Oct-6,1908.

, SHEETS-SHEET 2.

@MM 7 w UNITED strawssr OFFICE. 4

BRUNO V. NDRDBEBG, OF MILWAUKEE, WISCONSIN.

VARIABLE-CAPACITY COMPRESSOR.

Specification of Letters Patent.

Patented. Oct. 6, 1-908.

Applloationflled Ieptember B, 1908. Serial No; P125368.

To all whom it may concern:

Be it known that I, BRUNO V. Noannnso, a citizen of the United States, residing at Milwaukee in the county of Milwaukee and State of Wisconsin, have invented certain new and useful Improvements in Variable- Capacity Compressors, of which the, following is a specification, reference being bad to' the accompanying drawing, forming a part thereof. a

The object of this invention is 'to provide means for varying the quantity of air delivered by an air compressor running at a conor by unloadin stant speed. Under some constructions this has been accomplished either by throttlin the whole quantity of air before it enters the compressor, thereby reducing its density, the compressor; that 1s,

, either by estab ishing communication between the interior of the cylinder and the atmosphere, or by establishmg communication between the opposite ends of the cylinder or b stopping the delivery of air alto- EZ: er. he first method is objectionable arise by throttling the air the work of compressing is increased above that necessary to compress the same volume of air from atmospheric pressure to the re uired pressure. -The secondg'method is o. jectionable because the whole load of the compressor is put on or thrown off, thereby subjecting the motor to extreme variations of load, and since in most cases either electric motors or water wheelsflare employed to operate the compressors, this mo unsatisfactory.

e of regulation is .very According to the present twenties the load is increased or decreased exactl in proportion to the demand for air, t e compressor running at a constant speed.

The invention consists in certain novel v features of construction and in the peculiar arrangement and combinations of parts hereinafter particularly described and defined in the claims.

' In the accompanying drawing like char acters designate the same parts in theseveral figures.

Figure 1 is a side elevation 'of a compressor embodying the invention; Fig. 2 is a pressure diagram illustrating its operation; Fig;

- 3 is an enla ed vertical longitudinal section of one end 0 the cylinder, includin one set of valves, which are duplicated at t e other end of thefcylinder; tie a vertical sec- ,endofthiscy' tion of the regulator for automaticall varyin the point of tripping and closing t e inlet va ves; and Fig. 5 1s a detail view on an enlarged scale of automatic valve gearsnitable for the purpose. I

Referring to Fi s. 1 and 3,, a is the compressor cyllnder, the piston, cone of the inlet valves, which are preferably of the semirotative Corliss t pe, and (1 one of the discharge valves, w ch are of the self-acting puppet type desi ned to open whenever the pressure in the cy inder equals or slightly exceeds that in the discharge chest, an to close when there is an excess of pressure in the discharge chest. The inlet valves ma be operated by any suitable form of Corliss valve gear which can be adapted to release and close said inlet valves during any ortion of the suction stroke of the piston, t e valves being set so that they will open when the piston commences its suction stroke, or a little later, and will be ositively closed at the end" of each valve 0 and connected by a rod f with the piston of a dash pot g. h is the "valve 0 ening arm, loosely mounted on the stem' of t, e valve and movable independentlyof the arm e. 'i is the tripcam ivoted to the arm h, and 7' is the trip arm, which is also pivoted to the arm'h, and {has a crank pin en aging with said cam. 7c and l are the latch locks attached to the closing arm e and the trip arm 7' respectively. m is a wrist lever mounted on .the cylinder and connected by rods with the opening arms h. It is also connected by a rod with a rocker arm 'n,*'which is in turn I connected by a rod and strap with an eccentric 0 on the crank shaft pg I The automatic regulator which determines the point of tripping and closing the inlet valves, consists generally as shown in Fig-#4 'in connection with Fig. l, of av cylinder q mounted in a vertical position on this com-- pressor frame adplung er r fitted in the lower a weigh-ted'sleeve s fitted checking or retarding iylinderfq, a unger 1' and re upper end of said-sleeve, an a device for the movement of said 5 sleeve. ,This checking or rctardin device consists in the presentnase of a das fixed to the upper end of the sleeve 8, v

stand 'w on thecomplunger v, fixed to a pressor frame.

weighted by divided rings at,

the pressure which the tain, and it constitutes ing said pressure. ed below the plunger The sleeve '8 is The cylinder pot a, and a adjustably to determine compressor isto maina weight for de termingis connect- 1' with the discharge chest of the compressor or the reservoir into -which it delivers compressed air, by a -pipe y. ,,The sleeve 8 is connected by crank arms ena groove therein, with a rocker shaft -z, supported by the stand w. One arm of a T-lever 2, suspended shaft z,.is connected by spending arm 5 on sald shaft 2.

by a bar 3 from the; a rod 4 with a corre- The othertwo, arms of said lever 2 are connected by rods with the trip cams i.

rocker arm 6, which is. in turn connected by a rod nected by and with a The bar 3 is conand stra with an eccentric 7 on the crank shaft p. T e eccentric 0 through'the rocker arm n and wrist lever m, vibrates the valve 0 at or near the valve opening arms h so through a constant are,

and opens the inlet beginning of the suction strokes 'of the piston, if the cams 'L are in position to trip blocks and IL erm'it' the enga ement of the The va ves c are also positively closed at the ends .of-thesuction strokes of the,piston by arms-hengaging on their the action of the with the arms (2, in case the dash pots fail to promptl act. 40 ping an "closing the suction strokes of mined by the regulator, w connections hereinbefore described, moves ositions to disengage the isooner or later, according e pressure exerted on increase of pressurecauses sand the cams 'i' into :trip blocks 7: and

to th The timesor points of trip the inlet valves 0 relative to the iston' are deterich through the bedisengaged and the inlet valves to close earlier, 50. manner causes I The operat'onoftl fore 'de cr'ibe; Assummg that position to release may be while-fa decrease, of pressure in like sa d valvesto 1e compressor hereinbeclose later.

explained as follows the-regulator plunger 1" is, in a *theinletvalves c at the Eli/middle of the stroke of the istonb, as said piston makes the first. hal stroke, air is admitted into. the.;cylinder P wa rs t s "at wtrakeeheme,i l die -9 i wwli mm-tF g 2 i of its suction Part return movement lunger r. 'An P trip blocks to the further movement of the piston in the same direction cgauses this air to expand, as indicated by line 9.10, 10 indicating the end of the stroke at which the piston is re-' --verscd and commences its stroke. When the piston is at point 10 ofits stroke there is a vacuum in the cylinder, indicated by the line 10-11 on the'diagram; that is, the whole volume of'air admitted to the cylinder through the open inlet valve, as indicated by line 89, has pended to -a volume indicated by the line 8-1l, and instead'of being ata-tmospheric pressure it is now at a reduced cated by the distance 10'1 1- mospheric line 8 1. 1.

compression ressur e indi-' I elow the at-i Asthe piston upon now been ex? its return movement makesitscompression stroke, the air is compressedas indicated the curved line 1() =l2.,, At, point, 12 th pressure in the cylinder ceeds. that in the-discharge chest, v matic discharge valved towards-which the, piston moves 0 ens,an.d ai 'r i the dischar e c es halt n .stroke of t epist'on indicat z part of, the

equals" orsli htly egg-f it e auto- .bM-thali isde'livered into It will be obvious i e ifjp iiftiaseand closure of the inlet valve hadirotbecurred the point 9, as indicated on the said valve had remained open rin th as have then corrcsponde andthe volume of air dicated by the line 14 air during the compression p he expense-1 incide' with the lowe l p ar line 10-12,;but as the ai co sion' during this operation, heat to itby the walls ofthenc .linder; temperature isnot i that of the cylinder, reaches a poin'tffsayp M absorbs heatffioin th point, andtliere con crepancy between the ep; am the lower part 'of the. c

1012, as indicated b1 thesl EM (.1 p the diagram. This is actic 1 loss, ineiiicie'ndy due, method herein shown and iagrain, but t I 5 tire stroke 8- 1 1, the compressionl linewould.

-I claim:

1; In a variable capacity compressor the combination with the com ressor cylinder and piston and suction and ischarge valves,

of automatic valve releasing and operatin gear constructed and arranged to release an positively close the suction valve at different points in the suction stroke of the piston according to the varying demand on the compressor, said gear operating to advance the time of closing the suction valve to reduce the compression and being directly controlled in its action by pressure from the compressor while the compressor runs at a constant speed, substantially as described.

2. In a variable capacity compressor the combination with the cylinder, piston and suction'and discharge valves, of automatic valve releasing and operating gear construct ed and arranged to release and positively close the suction valve at different oints in the suction stroke of the piston an to keep said valve closed dur' the compression stroke of said piston, sai gear operating to advance the time of closing the suction valve to reduce the compression and being directly controlled in its action by pressure from the compressor while the com ressor runs at a combination with 0. cy

constant speed, substantial y as described.

3. In a variable capacity compressor the inder and piston, of a self acting discharge valve, a positively actuated suction valve and automatic valve releasing and operating gear constructed and arranged to release and close the suction valve at different oints in the suction stroke of the piston, sai gear operating to advance the time of closing the suction valve to reduce the compression-and being directly controlled in its action by pressure from the compressor, whereb the volume of air or gas compressed on t e return stroke is varied acsion chamber cording to the varying demand on the compressor while the compressor runs at a constant speed, substantially as described.

4, In a variable capacity compressor the combination with the compressor cylinder having suction and discharge valves, of autom'atic valve releasingand operating gear constructed and arranged to release and close thesuction valve at different points in the suction stroke of the compressor, said gear operating to advance the time of closing the su'ction valve to reduce the compression and a pressure regplator comprising an ex an-.

aving a movable part w ich is connected with the releasing mechanism of said valve gear and is actuated by pressure from the compressor while the compressor runs at a constant speed, su'bstantially as de- Scfibed. J 1i I,

In a variable capacityl compr'essor the c ination with the wmptefesor piston and a cylinder having suction and discharge a lves, of automatic 7 valve releasing and speed, substantially as described.

6. In a variable capacity compressor the combination with the compressor piston and a cylinder having suction and discharge valves, of automatic valve releasing and operating gear comprising a tri cam and constructed and arranged to re ease and close the suction valve at difl'erent points in the suction stroke of the piston, and a pressure regulator comprising an expansion chamber having a movable part, means connecting said movable part with the trip cam, and a spring and ad ustable weight forming a part of the connection between said mo vable part and. trip cam, the movable part oisaid' pressure regulator being actuated by ressure from the compressor to vary the v0 ume of air admitted to the compressor cylinder while the compressor runs at a constant speed, substantially as described.

7 In a variable capacity compressor the combination with the compressor piston and a cylinder having self acting discharge valves and suction valves, of automatic valve relbasing and operating gear having trip cams and constructedand arranged to release and close the suction valves at different points inthe suction stroke of. the piston and to keep said valves closed during the compression stroke, whereby the volume of a r or gas compressed on the return stroke is varied according to the varying demand on the compressor, and an automatic pressure regulator comprising an expansion chamber having a fluid pressure supply connection, a movable part, means connecting said movable part with the trip cams and a spring, weight and check or retarding device forming a art of the connection between said movab e part and trip cams, the movable part of said pressure regulator being actuated by pressure from the compressor to vary the volume of air admitted to the compressor cylinder while the compressor runs at a constant speed, substantlally as described.

8. In a variable capacity compressor the combination with the compressor cylinder and piston and suction and 'scharge 'valves, of automatic valve gear constructed and arranged to positively close thesuction valve! at any point in the suction stroke of the piss ton said valve remaimn'g closed during the the var 'ng demand on compressor, sub 10 entire compression stroke of the piston, and stentia y as described.

an automatic reguletor actuated by varia- In witness whereof, I hereto affix 'my signations in pressure produced by the comture in presence of two witnesses.

pressor and operating directly upon the BRUNOV NORDBERGT- valve gear whi e the compressor runs ate H constant speed to vary the volume of air ed- Witnesses: v mitted to the compressor cylinder from the 1 f CHAsL. Goss, full cylinder capaclty to zero} according to ALICE E. Gross 

